Chemicals Dashboard Help: Advanced Search
Advanced Search capabilities presently support mass spectrometry at this point with mass and formula searching. For an overview of capabilities, we recommend you watch this short video
Mass Search - is selected by default. This search searches the monoisotopic masses listed in the intrinsic properties field for each chemical. The search is based on the neutral molecule. It is possible to select various adducts and losses.
Molecular Formula Search - searches are based on inputting the elements according to Hill Formula convention. A list of formulae in Hill system order is arranged alphabetical with single-letter elements coming before two-letter symbols when the symbols begin with the same letter (so "B" comes before "Be", which comes before "Br"). The following formulae are written using the Hill system, and listed in Hill order: 1) BrI 2) CCl4 3) CH3I 4) C2H5Br 5) H2O4S
Three searches are available:
- MS Ready Formula: This search is based on what we refer to as "Mass Spec (MS) Ready" structures. All chemicals within the database are treated in a manner such that all are desalted, mixtures are separated, and stereochemistry is removed as Mass Spectrometry detects the major components of a salt or mixture and is insensitive to stereochemistry. As an example, a search for the molecular formula of phenol (i.e., C6H6O), will return phenol, sodium phenolate and calcium phenoxide (and many other results). See the publication for more details: “MS-Ready” structures for non-targeted high-resolution mass spectrometry screening studies"
- Exact Formula: The Exact Formula Search is the formula associated with single component chemicals as well as multicomponent mixtures and salts.
- Formula Contains (default): This search will find every molecular formula containing the queried element. Please limit search to only one element at a time.
Generate Molecular Formula(e) - Using a mass (and associated range in Daltons or ppm), molecular formulae are generated and then searched against the database to retrieve chemicals of interest. The elements used in the formula generation are CHNOPS by default but halogens and other elements can be included and their ranges defined using the option settings.
